A look at the care required to robustly parse a simple serial protocol.
This article looks at some of the bugs discovered in a library for the Plantower PMS5003 particulate matter sensor. This device uses a simple serial interface to send data at low speed to another device. The library sounds trivial to design and implement but it’s remarkably easy to produce a library with protocol parsing flaws.
The Pimoroni Enviro+ FeatherWing board has a connector for the PMS5003. The example code includes a plotting program which can graph the particulate data over time at different rates. The combined plotter program typically terminated with a ChecksumMismatchError exception after a minute or two when…
Kevin J. Walters
I write occasionally for Adafruit and on Instructables. https://learn.adafruit.com/users/kevinjwalters https://instructables.com/member/kevinjwalters/
